Hi and welcome!
Bedding can be confusing! Unless your hutch is in an insulated shed or outbuilding, I would not use fleece; that is usually better for indoors cages. Wood shavings are only recommended if dust extracted and straw is not at all recommended for guinea pigs (danger of eye pokes, as well as eing too rough), but there are several alternative loose bedding types that can replace wood shavings. I think that fitch is the one that is currently most popular with our members for outdoors accommodations. Soft hay makes good insulation in winter; hay should make up to 80% of the daily food intake anyway.
Here is our overview, which lists the pros and cons of all types:
https://www.theguineapigforum.co.uk/threads/bedding-for-guinea-pigs-overview.114219/
Our members' hutch gallery:
https://www.theguineapigforum.co.uk/threads/member-gallery-hutches.53209/
You are welcome to open a thread in our housing section for tips re. winter accommodation and summer/heat wave protection etc.
Since we have got members from all over the world, we find it helpful if you please added your country, state or (for the UK) your county to your details. This will enable us to give you tips and links that are appropriate for where you are straight away and will also avoid misunderstadings between members from different backgrounds and climates. Please click on your username on the top bar, then go to personal details and scroll down to location. Thanks!
Are you planning to get your guinea pigs from a good standard rescue? I would like to ask you to please consider this as the safest option to get guaranteed healthy, properly sexed, carefully bonded guinea pigs that are suited for newbies. It would help you to neatly avoid all the usual pitfalls that await the unwary. We have got a UK good standard piggy savvy rescue and piggy savvy vet locator on the top bar.
You can find lots more information at the top of our various Care sections, but you are welcome to ask any questions you may have at any point in one of our sections for best results.